Apheresis apparatus and method for producing blood products

Abstract

An apheresis machine is provided, which can efficiently produce concentrated platelets products without excessively collecting platelets. The apheresis machine 10 comprises a centrifuge 11 having an inlet port PT 1 and an outlet port PT 2 for separating whole blood into a lower density component, an intermediate density component and a higher density component, a first container 18 connected to receive the lower density component from the outlet port PT 2 and return it through the inlet port PT 1 to the centrifuge 11 , a first pump P 1 operated to collect whole blood from the inlet port PT 1 to the centrifuge 11 , a second pump P 2 operated to supply the lower density component from the first container 18 , and means for variable controlling the centrifuge 11 and/or the second pump P 2 for increasing or decreasing a process volume of whole blood in the centrifuge in response to at least one characteristic associated with the whole blood.

We claim:  
     
       1. An apheresis apparatus comprising: 
       a centrifuge for separating whole blood into a lower density component, an intermediate density component and a higher density component, said centrifuge having an inlet port and an outlet port;  
       a first container in selective fluid communication with said inlet port and said outlet port and connected to collect the lower density component from said outlet port and return the lower density component through said inlet port to said centrifuge;  
       a first pump operated for collecting whole blood through said inlet port into said centrifuge;  
       a second pump operated for supplying the lower density component from said first container to the whole blood collected by said first pump to said centrifuge; and  
       a controller having a computer readable medium encoded to perform a method, the method comprising:  
       calculating a process volume of whole blood per cycle in a multiple cycle process of said centrifuge as a function of at least one characteristic associated with the whole blood; and  
       variably controlling at least one of said centrifuge and said second pump by increasing or decreasing speed of rotation of the centrifuge and/or increasing or decreasing the amount of the lower density component supplied by the second pump to attain the process volume per cycle of whole blood.  
     
     
       2. The apparatus as claimed in  claim 1 , wherein said at least one characteristic of the whole blood is selected from the number of platelets, hematocrit value and total amount of the whole blood. 
     
     
       3. The apparatus as claimed in  claim 1 , wherein said method includes variably controlling at least one of said centrifuge and said second pump so as to increase or decrease a filling density of the higher density component within said centrifuge. 
     
     
       4. The apparatus as claimed in  claim 1 , wherein said method includes variably controlling at least one of said centrifuge and said second pump so as to decrease the process volume per cycle of whole blood in a multiple cycle process of said centrifuge. 
     
     
       5. The apparatus as claimed in  claim 1 , wherein said method includes increasing the amount of the lower density component supplied by the second pump so as to increase an average level of a flow rate of the lower density component circulated through said centrifuge, while also varying the amount of lower density component supplied by the second pump so as to compensate for fluctuations in a flow rate of the whole blood into said centrifuge. 
     
     
       6. An apheresis apparatus for performing a plurality of processing cycles, each processing cycle comprising: 
       operating a first pump for collecting whole blood;  
       separating the collected whole blood into a higher density component, an intermediate density-component and a lower density component; and  
       harvesting at least the intermediate density component and returning at least the higher density component;  
       wherein the apparatus comprises a second pump for using the lower density component to dilute the whole blood during collection, and  
       wherein the apparatus comprises a controller having a computer readable medium encoded to perform a method, the method comprising:  
       calculating a number of units of the intermediate density component to be harvested during one cycle in response to at least one characteristic associated with the whole blood, calculating a total number of cycles, and variably controlling a process volume of whole blood per cycle of the plurality of processing cycles by increasing or decreasing a filling density of the higher density component within said centrifuge so that the total number of units of the intermediate density component harvested from said total cycles equals a predetermined number of units.  
     
     
       7. The apparatus as claimed in  claim 6 , wherein said at least one characteristic of the whole blood is selected from the number of platelets, hematocrit value and total amount of the whole blood. 
     
     
       8. The apparatus as claimed in  claim 7 , wherein said method includes controlling the process volume of whole blood by stepwise changes in a control variable, and selecting said predetermined number of units from amongst a set of incrementally different values to be a value that is greater than, and closest of the set to, a target number of units of the intermediate density component. 
     
     
       9. The apparatus as claimed in  claim 6 , wherein said method includes variably controlling the process volume of whole blood per cycle by variably controlling at least one of said centrifuge and said second pump. 
     
     
       10. The apparatus as claimed in  claim 9 , wherein said method includes increasing or decreasing the process volume of whole blood per cycle by increasing or decreasing the speed of rotation of said centrifuge so as to increase or decrease a filling density of said higher density component within the centrifuge. 
     
     
       11. The apparatus as claimed in  claim 9 , wherein said method includes decreasing the process volume of whole blood per cycle by increasing the amount of the lower density component supplied by said second pump so as to decrease a filling density of the higher density component within the centrifuge. 
     
     
       12. The apparatus as claimed in  claim 11 , wherein said method includes increasing the amount of the lower density component supplied by the second pump so as to increase an average level of a flow rate of the lower density component into the whole blood during collection, while also varying the amount of lower density component supplied by the second pump so as to compensate for fluctuations in a flow rate of the whole blood into said centrifuge. 
     
     
       13. The apparatus as claimed in  claim 6 , wherein said centrifuge has an inlet port and an outlet port, the apparatus further comprising a first container in selective fluid communication with said inlet port and said outlet port and connected to collect the lower density component from said outlet port and return the lower density component through said inlet port to said centrifuge. 
     
     
       14. The apparatus as claimed in  claim 13 , further comprising a second container in selective fluid communication with said outlet port for collecting the intermediate density component displaced from the centrifuge. 
     
     
       15. The apparatus as claimed in  claim 14 , further comprising a third container in selective fluid communication with said outlet port for collecting a second intermediate density component that is different from said intermediate density component and is displaced from the centrifuge. 
     
     
       16. The apparatus as claimed in  claim 15 , wherein the lower density component is plasma, said intermediate density component is platelets, and said second intermediate density component is white blood cells. 
     
     
       17. The apparatus as claimed in  claim 6 , wherein said second pump is operated after collection of the whole blood for: 
       circulating the lower density component through said centrifuge at a substantially constant flow rate to dilute said intermediate density component within said centrifuge and to widen the region occupied by said intermediate density component within said centrifuge for improving its separation; and  
       supplying said lower density component at a surge flow rate through the centrifuge to displace said intermediate density component from said centrifuge.  
     
     
       18. The apparatus as claimed in  claim 17 , further comprising a sensor for monitoring the radius of the region occupied by said intermediate density component within said centrifuge and detecting when said radius has attained a predetermined value, said second pump beginning said circulation at said substantially constant flow rate in response to a detection at said sensor. 
     
     
       19. The apparatus as claimed in  claim 17 , wherein said substantially constant flow rate is greater than a flow rate at which the whole blood is collected. 
     
     
       20. The apparatus as claimed in  claim 17 , wherein said surge flow rate is greater than said substantially constant flow rate. 
     
     
       21. The apparatus as claimed in  claim 6 , further comprising a container for anticoagulant and means for combining whole blood with the anticoagulant before the whole blood enters said centrifuge. 
     
     
       22. The apparatus as claimed in  claim 17 , in which said second pump is operated for further supplying the lower density component through said centrifuge at a flow rate greater than said surge flow rate after supplying the intermediate density component at said surge flow rate. 
     
     
       23. A method for producing a blood product from collected whole blood, the method comprising performing more than one processing cycle, each cycle including the steps of: 
       supplying whole blood into a centrifuge;  
       separating the whole blood in said centrifuge into a higher density component, an intermediate density component and a lower density component;  
       supplying the lower density component for diluting the whole blood supplied to the centrifuge; and  
       harvesting at least said intermediate density component,  
       wherein the steps of supplying whole blood, separating the whole blood, supplying the lower density component, and harvesting are repeated for each cycle performed;  
       the method further comprising the step of determining a process volume per cycle of whole blood in response to at least one characteristic associated with the whole blood, wherein determining the process volume per cycle of whole blood is performed by increasing or decreasing speed of rotation of the centrifuge and/or increasing or decreasing the amount of the lower density component supplied by the second pump to attain the process volume per cycle of whole blood.  
     
     
       24. The method as claimed in  claim 23 , wherein said at least one characteristic of the whole blood is selected from the number of platelets, hematocrit value and total amount of the whole blood. 
     
     
       25. The method as claimed in  claim 23 , wherein determining the process volume per cycle of whole blood is performed to harvest said intermediate density component in a predetermined amount. 
     
     
       26. The method as claimed in  claim 23 , wherein determining the process volume of whole blood per cycle is performed by decreasing the speed of rotation of said centrifuge so as to decrease a filling density of said higher density component in said centrifuge and to decrease said process volume of whole blood per cycle. 
     
     
       27. The method as claimed in  claim 23 , wherein determining the process volume of whole blood per cycle is performed by increasing the amount of supply of the lower density component so as to decrease said process volume of whole blood per cycle. 
     
     
       28. The method as claimed in  claim 23 , wherein said lower density component is plasma, said intermediate density component is platelets and said higher density component is red blood cells. 
     
     
       29. A method for producing from collected whole blood a blood product of an intermediate density component at a predetermined number of units, the method comprising more than one cycle including the steps of: 
       supplying whole blood into a centrifuge;  
       rotating said centrifuge at a predetermined speed to separate the whole blood into a higher density component, an intermediate density component and a lower density component;  
       supplying the lower density component at a predetermined flow rate to dilute the whole blood supplied to said centrifuge; and  
       harvesting at least said intermediate density component;  
       said method further comprising the steps of:  
       determining in response to at least one characteristic associated with the whole blood the number of units of said intermediate density component to be harvested from one cycle;  
       determining the number of total cycles so as to exceed said predetermined number of units; and  
       determining a process volume of whole blood per cycle so that the total number of units of said intermediate density component harvested in said total cycles neighbors said predetermined number of units.  
     
     
       30. The method as claimed in  claim 29 , further comprising controlling said process volume of whole blood by stepwise changes in a control variable to change said total number of units of said intermediate density component; and wherein determining a process volume of whole blood per cycle is performed so as to attain a value of the total number of units of said intermediate density component that is greater than and closest, of a set of incrementally different values, to said predetermined number of units. 
     
     
       31. The method as claimed in  claim 29 , wherein said at least one characteristic is selected from the number of platelets, hematocrit value and total amount of the whole blood. 
     
     
       32. The method as claimed in  claim 29 , wherein determining the process volume of whole blood per cycle is performed by at least one of: increasing or decreasing said predetermined speed of rotation of said centrifuge; and increasing or decreasing said predetermined flow rate for supplying the lower density component. 
     
     
       33. The method as claimed in  claim 32 , wherein determining the process volume of whole blood per cycle is performed by decreasing the speed of rotation of said centrifuge to decrease a filling density of the higher density component within said centrifuge and to decrease the process volume of whole blood volume per cycle. 
     
     
       34. The method as claimed in  claim 32 , wherein determining the process volume of whole blood per cycle is performed by increasing said predetermined flow rate for supplying said lower density component to decrease the process volume of whole blood per cycle. 
     
     
       35. The method as claimed in  claim 29 , wherein said lower density component is plasma, said intermediate density component is platelets and said higher density component is red blood cells.